The object lit up and began glowing a bright, pale green as Jerry walked away from it. He stopped about fifteen feet away and placed another beacon-thing on the roof before turning ninety degrees and proceeding an equal distance to place another. Within a few seconds, there were four of the strange objects set in an approximate square.
"I think," whispered Nick, his words barely audible, "I think it is a landing pad."
"You've got to be kidding me."
He shrugged dismissively and began scanning the skies. I craned my head around the ventilation duct to keep my eyes on the twins. They had sat down near the door. Jerry seemed to be playing a game on his iPod, but Edwin was keeping vigilant watch. There was no way I would be able to escape from the roof without his noticing.
Nick pointed upward. Something--a helicopter by the sound of it--was approaching from the west, a blinding light shining down from its underbelly.
"Duck, or they'll see us!"
We made ourselves as small as possible and pretended to be inanimate objects. I'm not sure how convincing my acting was, so all I could hope was that nobody in the helicopter noticed us.
The craft hovered overhead for a moment then touched down amid the beacons, the wind from its noisy blades sending dust and dry leaves dancing about the roof. I took my head out from beneath my hands once more and watched. The twins were standing now, shielding their eyes against the bright light and buffeting breeze with their forearms, waiting for the occupants of the helicopter to emerge onto the roof. The hatch opened, and three figures in dark clothing jumped out, carrying large bundles and darting for the door with urgency in their steps. They shouted among each other over the sound of the helicopter, but Nick and I were too far away to make out their words. Edwin shouted something too, and one of the black-clad men thrust a wad of what appeared to be cash into the boy's outstretched hand. Then the three men vanished down the stairs, followed a few seconds later by the twins, and the helicopter lifted off and extinguished the bright light, flying away into the night. We were left alone on the roof in comparative silence.
Nick looked at me, his eyes wide. "I don't know what I just saw."
"Me neither," I replied. But I did know what I had just begun to hear: sirens. "Nick, I think it's time to get out of here before we become suspects in whatever it was we just saw."